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Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 18. Feb 2021, 12:24
by jmar83_the2nd
Screenshot here:

- ppp.JPG (36.99 KiB) Viewed 1509 times
Why that? Thank you for your feedbacks.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 18. Feb 2021, 14:31
by scottgus1
Please right-click the guest in the main Virtualbox window's guest list, choose Show Log.
Search the far left tab's log for this text:
Attempting fall back to NEM
If you find it, Hyper-V is enabled. See
HMR3Init: Attempting fall back to NEM (Hyper-V is active).
If you don't find that text, save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 22. Feb 2021, 13:15
by jmar83_the2nd
The problem is not reproduceable...
Andi was thinking the from >= Version 6.1.16, VirtualBox does not have problems anymore with Hyper-V coexistence...? But maybe, i didn't unstand that point correctly...?
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 22. Feb 2021, 17:21
by scottgus1
jmar83_the2nd wrote:from >= Version 6.1.16, VirtualBox does not have problems anymore with Hyper-V coexistence.
No, it's not over yet. 6.1.18 also continues to show the turtle. It's a running street battle yet.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 22. Feb 2021, 17:51
by jmar83_the2nd
OK thx.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 12:09
by jmar83_the2nd
So what's the solution? Installing Version 6.1.18 and then execute "bcdedit /set hypervisorlaunchtype off" or uninstalling Hyper-V engine completely. (I would NOT prefer to uninstall it completely, becase it like to create virtual network bridges in Hyper-V administration and using them in VirtualBox - maybe that sounds a lil bit strang - but however...;-))
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 13:27
by multiOS
The 'solution' is to learn how to toggle the Hyper-V 'engine' on and off as needed. It cannot be completely uninstalled because, once used, it's permanently embedded/available for activation in the Windows Operating System. See the final link in the Guide linked by scottgus1 in his earlier response for one 3rd-party guide on the options.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 13:33
by jmar83_the2nd
Or maybe there is also (in some environents) an issue with the Window$ "Data Execution Prevention" which causes problems (freeze on VM start) like that...?
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 17:55
by scottgus1
jmar83_the2nd wrote:an issue with the Window$ "Data Execution Prevention"
I have not seen in any Hyper-V tutorials indication that DEP causes VM's to crash or seize. Hyper-V definitely causes trouble for many Virtualbox users.
Turning off DEP might do other things.
As of yet we haven't seen that you specifically did or did not find the words "Attempting fall back to NEM" in your VM's log. If those words are there, then Hyper-V is enabled.
For now it's either Hyper-V or Virtualbox. Some folks with certain VMs can run Virtualbox with Hyper-V enabled. Most cannot. See the 6.0 & Hyper-V sticky for the saga
viewtopic.php?f=6&t=90853.
If you cannot get a VM to run and you see the green V turtle in the VM's status bar, then Hyper-V is on and must be turned off. The Hyper-V on/off toggle method is linked where multiOS says to look.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 17:56
by jmar83_the2nd
Thank you very much for your feedback!! :-)
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 19:12
by multiOS
From what I can remember from previous discussion threads, the only VirtualBox users who have reported 'successful', i.e. acceptable speed, VM operation with Hyper-V enabled were running 32-bit VMs, so you could try a 32-bit version of Debian if you really want to. Most derivative distributions and major alternatives, as you probably know, seem to have already moved, or are progressively moving towards 64-bit-only distributions, with multi-arch support for running 32-bit software.
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 25. Feb 2021, 20:24
by jmar83_the2nd
32 Bit is no option for me - so i'm sorry... ;-)
Re: Does not start anymore on Win10 Host with Debian 10 Guest
Posted: 1. Mar 2021, 14:29
by jmar83_the2nd
I still don't know what the problem was - whatever, it should be stable and NOT freeze while staring... with that issue, it's not useable for me because it's reliable.